European Journal of Plant Pathology (2019) 155, 1117-1132

Natasa Mehle, Nejc Jakos, Miro Mesl, Joze Miklavc, Bostjan Matko, Mojca Rot, Alenka Ferlez Rus, Robert Brus and Marina Dermastia (2019)
Phytoplasmas associated with declining of hazelnut (Corylus avellana) in Slovenia
European Journal of Plant Pathology 155 (4), 1117-1132
Abstract: Hazelnut (Corylus avellana) is cultivated on 118 ha and ranks eighth in Slovenian fruit growing production, representing 2.8% of the total area of fruit plantations in the country. However, decline of some of the trees appeared in 2012 in two plantations located in eastern Slovenia. Together these orchards cover 5 ha, with around 1600 trees planted 12 to 15 years ago. By October 2018, ~12% of these trees had died, and an additional 12% showed decay symptoms. The dead and dying trees were scattered throughout both orchards, with no apparent pattern. The most affected cultivar was 'Istrska dolgoplodna leska'. Using molecular diagnostic methods, we showed infection of symptomatic trees with three unrelated phytoplasmas: ' Candidatus Phytoplasma fragariae', of the 16SrXII-E phytoplasma subgroup, and phytoplasma of the 16SrV and 16SrIX groups. In 2018, the presence of ' Ca. P. fragariae' and/or phytoplasma of 16SrV group were confirmed in decayed hazelnut trees in eastern, north-eastern, central, south-eastern and western Slovenia. ' Ca. P. fragariae' has also been detected in a forest in south-western Slovenia, for Acer campestre, Carpinus betulus, Crataegus laevigata, Fraxinus ornus and Quercus petraea. All infected forest trees showed unusual dense proliferation of sprouts from roots and/or trunks. Molecular characterisations of partial 16S rRNA, secY, map and ribosomal protein genetic locus of hazelnut 16SrV phytoplasma isolates show that they are identical to isolates that can cause grapevine flavescence dorée disease. Here, the results of our recent study and the open questions on this burning issue for hazelnut production are presented.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Full text of article
Database assignments for author(s): Natasa Mehle

Research topic(s) for pests/diseases/weeds:
surveys/sampling/distribution

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	16SrV phytoplasma group	Hazelnut (Corylus)	Slovenia
	Phytoplasma fragariae	Hazelnut (Corylus)	Slovenia